In today's radio communications networks a number of different technologies are used, such as Long Term Evolution (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. A radio communications network comprises radio base stations providing radio coverage over at least one respective geographical area forming a cell. The cell definition may also incorporate frequency bands used for transmissions, which means that two different cells may cover the same geographical area but using different frequency bands. User equipments (UE) are served in the cells by the respective radio base station and are communicating with respective radio base station. The user equipments transmit data over an air or radio interface to the radio base stations in uplink (UL) transmissions and the radio base stations transmit data over an air or radio interface to the user equipments in downlink (DL) transmissions.
In 3rd Generation Partnership Project (3GPP) Release (Rel)-11, work is ongoing to improve the end user experience and performance especially in a CELL_FACH state. CELL_FACH state is a Radio Resource Control (RRC) state in which the user equipment is known on a cell level, i.e. has a cell ID, has a layer 2 connection but no dedicated physical layer resource. Instead, common physical layer resources are shared between user equipments in CELL_FACH state, whereas in CELL_DCH state user equipments have a dedicated physical resource.
Enhanced Dedicated Channel (E-DCH) may also be deployed in CELL_FACH state which is normally used as a dedicated channel in CELL_DCH state with one separate resource allocated per user equipment. In CELL_FACH state, this is performed by having a pool of E-DCH resources that may be temporarily assigned to a user equipment in CELL_FACH state. There resources may be called common E-DCH resources. Common E-DCH resources are normally managed by a Radio Network Controller (RNC) controlling one or more radio base station, but the pool of common E-DCH resources may be managed by the radio base station also referred to as NodeB. The common E-DCH configurations are broadcasted by the radio base station to user equipments in the cell.
The procedure to access the common E-DCH channel in CELL_FACH state starts in the same way as Release-99 Random Access Channel (RACH) transmission, i.e. with preamble power ramping using randomly selected preamble signatures. Having detected the preamble, the NodeB acknowledges reception with an Acquisition Indicator Channel (AICH) sequence. The NodeB also informs the user equipment which common E-DCH resource it has assigned to the user equipment.                A common E-DCH resource is defined as or comprises        UL scrambling code        E-DCH Radio Network Temporary Identifier (E-RNTI)        Fractional-Dedicated Physical Channel (F-DPCH) code and timing offset E-DCH Absolute Grant Channel (E-AGCH)/E-DCH-Relative Grant Channel (E-RGCH)/E-DCH Hybrid Automatic Repeat Request (HARQ) Acknowledgement Indicator Channel (E-HICH) codes and signatures; and parameters for use by the user equipment in uplink High-Speed Dedicated Physical Control Channel (HS-DPCCH) transmissions, such as power offsets and Channel Quality Report configuration information, e.g. a Channel Quality Indicator (CQI).        
CELL_FACH state in Release 10 of 3GPP is a state commonly used for battery and radio efficient use of radio resources for user equipments in which data typically arrive in bursts with longer idle periods in between. Ideally, a user equipment should be inactive between the bursts but still be capable of swiftly moving into an active state when there are packets to send or receive. For this kind of on-off type traffic patterns, the connection set-up latency and signaling load has a significant impact both on the preservation of the battery of the user equipment and on the transmission quality perceived by the end user of the user equipment.
E-DCH resource configurations are broadcasted in System Information Block 5 (SIB5). Some of the broadcasted parameters are common for all common E-DCH resources, for instance the Time Transmission Interval (TTI) configuration. E-DCH as specified nowadays may have two TTI configuration: 2 ms and 10 ms transmissions. The 2 ms TTI E-DCH uses a total of 8 HARQ independent or individual processes meanwhile 10 ms TTI uses 4 HARQ independent or individual processes.
The deployment of 2 ms TTI in CELL_DCH state allows the possibility of activate or deactivate HARQ individual processes by the means of absolute grants, this possibility is not available for the 10 ms configuration. The activation/deactivation of HARQ processes provides to the network, e.g. Radio network Controller (RNC) or NodeB, with more flexibility to schedule rates and steer interference of the UE's transmissions. The activation/deactivation is done by means of the Absolute Grant Channel (AGCH), which signals to a specific user equipment a grant with two parameters; SCOPE parameter and GRANT parameter. Upon reception of an AGCH signal, the user equipment applies the GRANT parameter to the HARQ processes specified by the SCOPE parameter. The SCOPE parameter may be “ALL” or “Per-HARQ”; meaning that the grant applies to all the HARQ processes or to one specific process, e.g. the timing of the reception will determine which process is affected. The GRANT parameter, also referred to as GRANT value, may be mapped to the absolute grant table specified on table 16B and 16B.1 of 3GPP 25.212, version 10.1.0, see Table 1 below. If the GRANT value is equal to “INACTIVE” the HARQ process(es) referenced by the SCOPE parameter are deactivated. An active HARQ process indicates transmission from the user equipment for that TTI, and inactive HARQ process indicates a non-transmission from the user equipment for that respective TTI.
TABLE 1Absolute Grant Value defined by an index valueAbsolute Grant ValueIndex  (168/15)2 × 631  (150/15)2 × 630  (168/15)2 × 429  (150/15)2 × 428  (134/15)2 × 427  (119/15)2 × 426  (150/15)2 × 225   (95/15)2 × 424(168/15)2 23(150/15)2 22(134/15)2 21(119/15)2 20(106/15)2 19(95/15)218(84/15)217(75/15)216(67/15)215(60/15)214(53/15)213(47/15)212(42/15)211(38/15)210(34/15)29(30/15)28(27/15)27(24/15)26(19/15)25(15/15)24(11/15)23 (7/15)22ZERO_GRANT*1INACTIVE*0
In CELL_DCH state, the data flows, e.g. Medium Access Control-dedicated (MAC-d) flows, may be configured as scheduled or non-scheduled. The scheduled flows are transmitted following a set of rules specified in the transport format selection for E-DCH in 3GPP TS 25.321 version 10.3.0 based in scheduling grants that are transmitted to the user equipment by the network using the Absolute Grants Channels (AGCH), the Relative Grant Channels (RGCH) and the initial configuration message.
The scheduling grants limit the quantity of power that the user equipment may use to transmit data of the scheduled flows which is translated in a data rate when the user equipment power configuration is applied as well. Meanwhile, the non-scheduled flows are transmitted based in a non-schedule grant that is specified in the flow configuration message. The grant is in practice a limitation in the number of bits per Medium Access Control-enhanced (MAC-e) Packet Data Units (PDU) that can be used by the configured non-scheduled flow. The grant may be defined as a maximum power offset allowed to be used for the data transmission part that can be translated in a limitation in the number of bits. Non-scheduled flows are transmitted according to the absolute priority rules with respect to all the other flows and not needing to follow the current scheduling grant, but the initially specified non-scheduled grant. One important difference of schedule and non-schedule grants is that the AGCH and RGCH are controlled by the NodeB meanwhile an initial configuration used to configured the flow, schedule and non-schedule, are controlled by the RNC. The initial configuration permits to specify what processes are allowed to be used to transport non-scheduled data and what processes could transmit scheduled data from the scheduled flows. The initial configuration uses a HARQ process bitmap based in the process-Id to identify what process are allowed to send schedule or non-schedule data. This type of initial configuration is not available for CELL_FACH common E-DCH resources and the division between scheduled and non-scheduled data is not present either.
The expected increase in the number of user equipments in the CELL_FACH state added to the bursty, scatter with high packet size diversity characteristics of the traffic displayed by the majority of the smartphone type of user equipments makes the network resources a critical asset which requires and optimal handling.
By deactivating some of the HARQ processes in the 2 ms TTI Enhanced Uplink (EUL) transmissions, the network is available to utilize better its resources and support a higher number of user equipments' transmissions than allowing transmissions with all the HARQ processes. This is not possible in CELL_FACH state today since the scope of the absolute grants for the transmissions of EUL in CELL_FACH as introduced in Rel-8 will always apply to all HARQ processes. Even when the same mechanisms applied for CELL_DCH state are possible to be used to deactivate dynamically some of the HARQ processes this cannot be applied fully until the network has fully acknowledge the user equipment, after contention resolution phase, and therefore the initial state of the HARQ processes needs to be configured in advance. The initial configuration used in CELL_DCH state does not apply for directly activating or deactivating HARQ processes but to allow transmission of schedule and non-schedule data, concepts that are not defined for CELL_FACH state. A very basic signaling has been suggested but with an added overhead (size) of the signaling. The relative broadcasted signaling as specified in 3GPP TS 25.331 version 10.4.0 section 10.3.6.9a Common E-DCH system info. Using a dedicated signalling of the HARQ configuration, results in an increased usage of radio resources that also reduces performance of the radio communications.